Publication Details
Abstract
This research provides an innovative laboratory procedure for producing quality liquid soap from waste cooking oil (WCO). The two-step sequential green pretreatment improved quality: acid value was reduced from 1.50 ± 0.05 to 1.10 ± 0.03 mg KOH/g and 400 nm absorbance went from 0.50 ± 0.02 to 0.38 ± 0.01. Saponification of the pretreated oil yields high-quality liquid soap (13.0 ± 0.5% active) with pH of 8.5 ± 0.1, which is safe for skin; has good foam stability (88%); and aroma-free, confirmed by formal sensory test. The product showed good physical/chemical stability throughout a four-week accelerated storage test. The procedure is based on utilizing non-toxic materials that are readily available, allowing for a functional and sustainable circular economy solution for WCO.